diff options
| author | Sean Christopherson <seanjc@google.com> | 2022-08-31 02:16:14 +0300 |
|---|---|---|
| committer | Paolo Bonzini <pbonzini@redhat.com> | 2022-09-26 19:03:12 +0300 |
| commit | 40aaa5b6dadc2cbdfff004c31fdd00b9684ff1a8 (patch) | |
| tree | 85318ee7e807874e6de1c6fd673b948cfad247b1 /arch/x86/kvm/x86.c | |
| parent | 28c40b2cfb841d55f9f10fd973e1a72e0bf09572 (diff) | |
KVM: x86: Allow force_emulation_prefix to be written without a reload
Allow force_emulation_prefix to be written by privileged userspace
without reloading KVM. The param does not have any persistent affects
and is trivial to snapshot.
Signed-off-by: Sean Christopherson <seanjc@google.com>
Link: https://lore.kernel.org/r/20220830231614.3580124-28-seanjc@google.com
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Diffstat (limited to 'arch/x86/kvm/x86.c')
| -rw-r--r-- | arch/x86/kvm/x86.c | 7 |
1 files changed, 4 insertions, 3 deletions
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c index c0d5d512edfa..a532b9dea57b 100644 --- a/arch/x86/kvm/x86.c +++ b/arch/x86/kvm/x86.c @@ -179,7 +179,7 @@ EXPORT_SYMBOL_GPL(enable_vmware_backdoor); */ #define KVM_FEP_CLEAR_RFLAGS_RF BIT(1) static int __read_mostly force_emulation_prefix; -module_param(force_emulation_prefix, int, 0444); +module_param(force_emulation_prefix, int, 0644); int __read_mostly pi_inject_timer = -1; module_param(pi_inject_timer, bint, S_IRUGO | S_IWUSR); @@ -7287,6 +7287,7 @@ static int kvm_can_emulate_insn(struct kvm_vcpu *vcpu, int emul_type, int handle_ud(struct kvm_vcpu *vcpu) { static const char kvm_emulate_prefix[] = { __KVM_EMULATE_PREFIX }; + int fep_flags = READ_ONCE(force_emulation_prefix); int emul_type = EMULTYPE_TRAP_UD; char sig[5]; /* ud2; .ascii "kvm" */ struct x86_exception e; @@ -7294,11 +7295,11 @@ int handle_ud(struct kvm_vcpu *vcpu) if (unlikely(!kvm_can_emulate_insn(vcpu, emul_type, NULL, 0))) return 1; - if (force_emulation_prefix && + if (fep_flags && kvm_read_guest_virt(vcpu, kvm_get_linear_rip(vcpu), sig, sizeof(sig), &e) == 0 && memcmp(sig, kvm_emulate_prefix, sizeof(sig)) == 0) { - if (force_emulation_prefix & KVM_FEP_CLEAR_RFLAGS_RF) + if (fep_flags & KVM_FEP_CLEAR_RFLAGS_RF) kvm_set_rflags(vcpu, kvm_get_rflags(vcpu) & ~X86_EFLAGS_RF); kvm_rip_write(vcpu, kvm_rip_read(vcpu) + sizeof(sig)); emul_type = EMULTYPE_TRAP_UD_FORCED; |